Printed circuit boards used in electronic devices, such as a computer, have predetermined patterns (made of copper or the like) formed on one side or on each side of an insulating substrate or board. Such printed circuit boards can be manufactured by the following process. First, a laminate, composed of a photosensitive resin (photoresist) layer and a light-permeable resin cover film protecting the photosensitive resin layer, is laminated onto an electrically-conductive layer on an insulating board under heat and pressure. Then, a wiring pattern film is superposed on the laminate, and the photosensitive resin layer is exposed for a predetermined period of time through the wiring pattern film and the cover film. Then, after the cover film is removed, the exposed photosensitive resin layer is developed to thereby form an etching mask pattern. Thereafter, the unnecessary portions of the electrically-conductive layer are removed by etching and, further, the remaining photosensitive resin layer is removed, thereby forming a printed wiring board having a predetermined wiring pattern.
In the above process of manufacturing the printed circuit board, a step of peeling the cover film prior to developing the exposed photosensitive resin layer, is required. Conventionally, the separation of the cover film is carried out manually. Since the cover film is thin, exceptional dexterity and skill are required so that the photosensitive resin layer is not damaged or destroyed due to irregularities in the separation force applied by the worker.
For this reason, an automatic film peeling apparatus has been developed for automatically effecting the cover film peeling step.
One such conventional film peeling apparatus, is disclosed in Japanese Patent Application No. 101909/88, filed earlier by the Applicant of the present application. In that earlier apparatus, part of a film bonded to a board is manually separated therefrom. Then the automatic film separation is started at that portion of the film immediately adjacent to the manually separated part, and after its complete removal, the film is discharged. More specifically, such film peeling apparatus comprises a first film transfer structure that holds the separated portion of the film and moves or transfers the film upward from the top planar surface of the board so as to separate the film from the board, and a second film transfer structure for blowing a fluid (e.g. air) onto the film, transferred by the first film transfer structure, so as to transfer the film to a separated film-receiving structure.
However, in the conventional film peeling apparatus, the film may become stuck on a wall of an air duct through which the film, passes as it is transferred to the separated film-receiving structure by the air blown onto the film. This results in the blocking of the air duct and presents significant difficulties in achieving a continuous efficient operation.
An object of this invention is to provide a film peeling method by which a film bonded to a board is transferred and discharged while peeling the film from the board, and an incomplete transfer of the separated film is minimized.
Another object of the invention is to provide a technique by which a film peeling apparatus is simplified in construction, thereby facilitating the operation and maintenance of the apparatus.
The above and other objects and novel features of the invention will become manifest upon making reference to the description of the specification and accompanying drawings.